Synergistic combination of microbicides to combat fungi on plants

ABSTRACT

A plant-microbicidal composition having synergistic action, comprising at least two active ingredient components, wherein component I is a compound selected from the group 
     (IA) 1-[3-(2-chlorophenyl)-2-(4-fiuorophenyl)oxiran-2-ylmethyl]-1H-1,2,4-triazole (&#34;epoxiconazol&#34;); 
     (IB) 4-(4-chlorophenyl)-2-phenyl-2-(1,2,4-triazol-1-ylmethyl)-butyronitrile (&#34;fenbuconazol&#34;); 
     (IC) 5-(4-chlorobenzyl)-2,2-dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)-cyclopentanol (&#34;metconazol&#34;); 
     (ID) 2-(2,4-dichlorophenyl)-3-(1H-1,2,4-triazol-1-yl)propyl-1,1,2,2-tetrafluoroethyl ether (&#34;tetracon azol&#34;); 
     (IE) α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (&#34;tebuconazol&#34;); 
     (IF) 1-[4-bromo-2-(2,4-dichlorophcnyl)tetrahydrofurfuryl]-1H-1,2,4-triazole (&#34;bromuconazol&#34;); 
     or in each case one of the salts or metal complexes thereof; 
     and component II is 
     (IIA) 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole (&#34;propiconazol&#34;) and/or 
     (IIB) 4-cyclopropyl-6-methyl-N-phenyl-2-pyrimidineamine (&#34;cyprodinil&#34;), 
     or in each case one of the salts or metal complexes thereof.

The present invention relates to novel microbicidal active ingredientmixtures having synergistically enhanced action, comprising at least twoactive ingredient components, and to methods of using such mixtures inplant protection.

Component I is a compound selected from the group:

(IA)1-[3-(2-chlorophenyl)-2-(4-fluorophenyl)oxiran-2-ylmethyl]-1H-1,2,4-triazole("epoxiconazol"; reference: EP-A-196 038);

(IB)4-(4-chlorophenyl)-2-phenyl-2-(1,2,4-triazol-1-ylmethyl)-butyronitrile("fenbuconazol"; reference: EP-A-251 775);

(IC)5-(4-chlorobenzyl)-2,2-dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)-cyclopentanol("metconazol"; reference: EP-A-267 778);

(ID)2-(2,4-dichlorophenyl)-3-(1H-1,2,4-triazol-1-yl)propyl-1,1,2,2-tetrafluoroethylether ("tetraconazol"; reference: EP-A-234 242);

(IE)α-[2-(4-chlorophenyl)ethyl]α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol("tebuconazol"; reference: EP-A-40 345);

(IF) 1-[4-bromo-2-(2,4-dichlorophenyl)tetrahydrofurfuryl]-1H-1,2,4-triazole ("bromuconazol"; reference EP-A-246 982),

or in each case one of the salts or metal complexes thereof; and

component II is the compound:

(IIA)1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole("propiconazol"; reference: GB-1 522 657) and/or

(IIB) 4-cyclopropyl-6-methyl-N-phenyl-2-pyrimidineamine ("cyprodinil";reference: EP-A-310 550)

or in each case one of the salts or metal complexes thereof.

Of the acids that can be used for the preparation of salts of compoundsof formulae I and II, the following may be mentioned:

hydrohalic acids, such as hydrofluoric acid, hydrochloric acid,hydrobromic acid or hydriodic acid; sulfuric acid, phosphoric acid,nitric acid; and organic acids, such as acetic acid, trifluoroaceticacid, trichloroacetic acid, propionic acid, glycolic acid, thiocyanicacid, lactic acid, succinic acid, citric acid, benzoic acid, cinnamicacid, oxalic acid, formic acid, benzenesulfonic acid, p-toluenesulfonicacid, methanesulfonic acid, salicylic acid, p-aminosalicylic acid,2-phenoxybenzoic acid, 2-acetoxybenzoic acid and1,2-naphthal-ene-disulfonic acid.

The term salts also includes metal complexes of basic components I andII. Those complexes may as desired involve only one component or bothcomponents independently. It is also possible to produce metal complexesin which the two active ingredients I and II are linked to one anotherto form a mixed complex.

Metal complexes consist of the underlying organic molecule and aninorganic or organic metal salt, for example a halide, nitrate, sulfate,phosphate, acetate, trifluoroacetate, trichloroacetate, propionate,tartrate, sulfonate, salicylate, benzoate, etc., of an element of maingroup II, such as calcium and magnesium, and of main groups III and IV,such as aluminium, tin or lead, and of subgroups I to VIII, such aschromium, manganese, iron, cobalt, nickel, copper, zinc, etc..Preference is given to the subgroup elements of the 4th period. Themetals may have any of the different valencies in which they occur. Themetal complexes can be mono- or poly-nuclear, i.e. they can contain oneor more organic molecule components as ligands.

Further agrochemical active ingredients, such as insecticides,acaricides. nematicides, herbicides, growth regulators and fertilisers,but especially additional microbicides, may also be added to the activeingredient mixture according to the invention.

Synergistic mixtures are known wherein

a) component I is compound IA ("epoxiconazol") and component II iscompound IIB ("cyprodinil");

b) component I is compound IB ("fenbuconazol") and component II iscompound IIB ("cyprodinil");

c) component I is compound IE ("tebuconazol") and component II iscompound IIB ("cyprodinil") (reference for a), b) and c): EP-A-548 025);and

d) component I is compound IE ("tebuconazol") and component II iscompound IIA ("propiconazol") (reference: EP-A-393 746).

The present invention does not relate to those mixtures.

It has now been found, surprisingly, that the fungicidal action ofmixtures according to the invention of components I and II is not merelyadditive but is clearly synergistically enhanced.

Preference is given to two-component mixtures wherein

(1) component I is a compound selected from the group IA("epoxiconazol"),

IB ("fenbuconazol"), IC ("metconazol"), ID ("tetraconazol") and IE("tebuconazol"); and

component II is compound IIA ("propiconazol") and/or IIB ("cyprodinil");

(2) component I is a compound selected from the group IA("epoxiconazol"),

IB ("fenbuconazol"), IC ("metconazol"), ID ("tetraconazol") and IF("bromuconazol"); and

component II is compound IIA ("propiconazol");

(3) component I is a compound selected from the group IC ("metconazol"),

ID ("tetraconazol") and IF ("bromuconazol"); and

component II is compound IIB ("cyprodinil").

(4) A further preferred group is formed by three-component mixtureswherein component I is a compound selected from the group IA("epoxiconazol"),

IB ("fenbuconazol"), IC ("metconazol"), ID ("tetraconazol"), IE("tebuconazol") and IF ("bromuconazol"); and

component II is a mixture of IIA ("propiconazol") and IIB ("cyprodinil")and the ratio by weight of IIA:IIB=1:6 to 6:1.

(5) Of the above, preference is given especially to three-componentmixtures wherein component I is compound IE ("tebuconazol") and

component II is a mixture of

IIA ("propiconazol") and IIB ("cyprodinil").

The present invention relates also to a method of controlling fungiwhich comprises treating a site infested by or threatened withinfestation by fungi with, in any desired sequence or simultaneously, a)a compound of formula I or one of the salts thereof and b) the compoundof formula II or one of the salts thereof, it being possible also forthe salts to be so selected that the two compounds are bonded to an acidradical or, in the case of a metal complex, to a central metal cation.

Advantageous mixing ratios of the two compounds are I:II=1:10 to 10:1,preferably I:II=1:6 to 6:1 and especially I:II=1:3 to 3:1.

Other advantageous mixing ratios I:II are, for example, 1:1, 1:2, 1:4,2:1, 2:3.

In the three-component mixtures, preferred mixing ratios IIA:IIB forcomponent II =1:6 to 6:1 and especially 1:5 to 1:1.

The compound mixtures I+II according to the invention have veryadvantageous curative, preventive and systemic fungicidal properties forprotecting plants. The compound mixtures of the invention can be used toinhibit or to destroy the microorganisms occurring on plants or on pansof plants (the fruit, blossom, leaves, stems, tubers or roots) ofdifferent crops of useful plants, while at the same time parts of plantsthat grow later are also protected against such microorganisms. They canalso be used as dressings in the treatment of plant propagationmaterial, especially seed (fruit, tubers, grains) and plant cuttings(for example rice), to provide protection against fungal infections andagainst phytopathogenic fungi occurring in the soil. The compoundmixtures according to the invention are distinguished by the fact thatthey are especially well tolerated by plants and are environmentallyfriendly.

The compound mixtures are effective against phytopathogenic fungibelonging to the following classes: Ascomycetes (e.g. Venturia,Podosphaera, Erysiphe, Monilinia, Uncinula); Basidiomycetes (e.g. thegenera Hemileia, Rhizoctonia, Puccinia); Fungi imperfecti (e.g.Botrytis, Helminthosporium, Rhynchosporium, Fusarium, Septoria,Cercospora, Alternaria, Pyricularia and Pseudocercosporellaherpotrichoides); and Oomycetes (e.g. Phytophthora, Peronospora, Bremia,Pythium and Plasmopara).

Target crops to be protected within the scope of the present inventioncomprise, for example, the following species of plants: cereals: (wheat,barley, rye, oats, rice, sorghum and related species); beets: (sugarbeet and fodder beet); ponies, stone fruit and soft fruit: (apples,pears, plums, peaches, almonds, cherries, strawberries, raspberries andblackberries); leguminous plants: (beans, lentils, peas and soybeans);oil plants: (rape, mustard, poppy, olives, sunflowers, coconut, castoroil plants, cocoa beans and groundnuts); cucumber plants: (marrows,cucumber and melons); fibre plants: (cotton, flax, hemp and jute);citrus fruit: (oranges, lemons, grapefruit and mandarins); vegetables:(spinach, lettuce, asparagus, cabbages, carrots, onions, tomatoes,potatoes and paprika); lauraceae: (avocados, cinnamon and camphor); orplants such as maize, tobacco, nuts, coffee, sugar cane, tea, vines,hops, bananas and natural rubber plants, as well as ornamentals(flowers, shrubs, broad-leaved trees and evergreens, such as conifers).That list does not represent any limitation.

The compound mixtures according to the invention are especiallyadvantageous for applications in cereals, especially in wheat andbarley.

The mixtures of compounds of formulae I and II are generally used in theform of compositions. The compounds of formulae I and II can be appliedto the area or plant to be treated, either simultaneously or insuccession on the same day, together with, where appropriate, furthercarriers, surfactants or other application-promoting adjuvantscustomarily employed in formulation technology.

Suitable carriers and adjuvants may be solid or liquid and aresubstances ordinarily employed in formulation technology, for examplenatural or regenerated mineral substances, solvents, dispersants,wetting agents, tackifiers, thickeners, binders or fertilisers.

A preferred method of applying a compound mixture comprising at leastone of each of compounds I and II is application to the parts of theplants that are above the soil, especially to the leaves (foliarapplication). The frequency and rate of application depend on thebiological and climatic living conditions of the pathogens. Thecompounds can, however, also penetrate the plants through the roots viathe soil (systemic action) if the locus of the plant is impregnated witha liquid formulation (for example in rice culture), or if the compoundsare introduced in solid form into the soil, e.g. in the form of granules(soil application). In order to treat the seed, the compounds offormulae I and II may also be applied to the seeds (coating) either byimpregnating the tubers or grains with a liquid formulation of each ofthe compounds in succession or by coating them with an already combinedwet or dry formulation. In addition, in special cases, other methods ofapplication to plants are possible, e.g. treatment directed at the budsor the fruit.

The compounds of the combination are used in unmodified form orpreferably together with the adjuvants conventionally employed informulation technology, and are therefore formulated in known manner,e.g. into emulsifiable concentrates, coatable pastes, directly sprayableor dilutable solutions, dilute emulsions, wettable powders, solublepowders, dusts or granules, or by encapsulation in e.g. polymersubstances. As with the nature of the compositions, the methods ofapplication, such as spraying, atomising, dusting, scattering, coatingor pouring, are chosen in accordance with the intended objectives andthe prevailing circumstances. Advantageous rates of application of theactive ingredient mixture are generally from 50 g to 2 kg a.i./ha,preferably from 100 g to 1000 g a.i./ha, especially from 400 g to 1000 ga.i./ha. In the case of the treatment of seed, the rates of applicationare from 0.5 g to 1000 g, preferably from 5 g to 100 g, a.i. per 100 kgof seed.

The formulations are prepared in known manner, e.g. by homogeneouslymixing and/or grinding the active ingredients with extenders, e.g.solvents, solid carriers and, where appropriate, surface-activecompounds (surfactants).

Suitable solvents are: aromatic hydrocarbons, preferably the fractionscontaining 8 to 12 carbon atoms, such as xylene mixtures or substitutednaphthalenes, phthalates, such as dibutyl or dioctyl phthalate,aliphatic hydrocarbons, such as cyclohexane or paraffins, alcohols andglycols and their ethers and esters, such as ethanol, ethylene glycol,ethylene glycol monomethyl or monoethyl ether, ketones, such ascyclohexanone, strongly polar solvents, such as N-methyl-2-pyrrolidone,dimethyl sulfoxide or dimethylformamide, and vegetable oils orepoxidised vegetable oils, such as epoxidised coconut oil or soybeanoil; and water.

The solid carriers used, e.g. for dusts and dispersible powders, arenormally natural mineral fillers, such as calcite, talcum, kaolin,montmorillonite or attapulgite. In order to improve the physicalproperties it is also possible to add highly dispersed silicic acid orhighly dispersed absorbent polymers. Suitable granulated adsorptivecarriers are porous types, for example pumice, broken brick, sepioliteor bentonire; and suitable nonsorbent carriers are e.g. calcite or sand.In addition, a great number of pregranulated materials of inorganic ororganic nature can be used, such as especially dolomite or pulverisedplant residues.

Depending on the nature of the compounds of formulae I and II to beformulated, suitable surface-active compounds are non-ionic, cationicand/or anionic suffactants having good emulsifying, dispersing andwetting properties. The term "surfactants" will also be understood ascomprising mixtures of surfactants.

Especially advantageous application-promoting adjuvants are also naturalor synthetic phospholipids from the series of cephalins and lecithins,such as phosphatidylethanolamine, phosphatidylserine,phosphatidylglycerol and lysolecithin.

The agrochemical compositions generally comprise 0.1 to 99%, preferably0.1 to 95%, of compounds of formulae I and II, 99.9 to 1%, preferably99.9 to 5%, of a solid or liquid adjuvant and 0 to 25%, preferably 0.1to 25%, of a surfactant.

Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ dilute formulations.

The Examples that follow serve to illustrate the invention, "activeingredient" denoting a mixture of compound I and compound II in aspecific mixing ratio.

Formulation Examples

    ______________________________________                                        Wettable powders    a)       b)     c)                                        ______________________________________                                        active ingredient   25%      50%    75%                                       [I:II = 1:3(a), 1:2(b), 1:1(c)]                                               sodium lignosulfonate                                                                              5%       5%    --                                        sodium laurylsulfate                                                                               3%      --      5%                                       sodium diisobutylnaphthalene-                                                                     --        6%    10%                                       sulfonate                                                                     octylphenol polyethylene glycol                                                                   --        2%    --                                        ether (7-8 mol of ethylene oxide)                                             highly dispersed silicic acid                                                                      5%      10%    10%                                       kaolin              62%      27%    --                                        ______________________________________                                    

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording wettablepowders which can be diluted with water to give suspensions of thedesired concentration.

    ______________________________________                                        Emulsifiable concentrate                                                      ______________________________________                                        active ingredient (I:IIA:IIB = 1:1:4)                                                                10%                                                    octylphenol polyethylene glycol ether                                                                 3%                                                    (4-5 mol of ethylene oxide)                                                   calcium dodecylbenzenesulfonate                                                                       3%                                                    castor oil polyglycol ether                                                                           4%                                                    (35 mol of ethylene oxide)                                                    cyclohexanone          30%                                                    xylene mixture         50%                                                    ______________________________________                                    

Emulsions of any required dilution, which can be used in plantprotection, can be obtained from this concentrate by dilution withwater.

    ______________________________________                                        Dusts               a)       b)     c)                                        ______________________________________                                        active ingredient    5%       6%     4%                                       [I:II = 1:4(a); 1:5(b) and 1:1(c)]                                            talcum              95%      --     --                                        kaolin              --       94%    --                                        mineral filler      --       --     96%                                       ______________________________________                                    

Ready-for-use dusts are obtained by mixing the active ingredient withthe carrier and grinding the mixture in a suitable mill. Such powderscan also be used for dry dressings for seed.

    ______________________________________                                        Extruder granules                                                             ______________________________________                                        active ingredient (I:II = 1:1.5)                                                                   15%                                                      sodium lignosulfonate                                                                               2%                                                      carboxymethylcellulose                                                                              1%                                                      kaolin               82%                                                      ______________________________________                                    

The active ingredient is mixed and ground with the adjuvants, and themixture is moistened with water. The mixture is extruded and then driedin a stream of air.

    ______________________________________                                        Coated granules                                                               ______________________________________                                        active ingredient (I:II = 3:5)                                                                        8%                                                    polyethylene glycol (mol. wt. 200)                                                                    3%                                                    kaolin                 89%                                                    ______________________________________                                         (mol. wt. = molecular weight)                                            

The finely ground active ingredient is uniformly applied, in a mixer, tothe kaolin moistened with polyethylene glycol. Non-dusty coated granulesare obtained in this manner.

    ______________________________________                                        Suspension concentrate                                                        ______________________________________                                        active ingredient       40%                                                   (I:IIA:IIB = 1:2:5)                                                           propylene glycol        10%                                                   nonylphenol polyethylene glycol ether                                                                  6%                                                   (15 mol of ethylene oxide)                                                    sodium lignosulfonate   10%                                                   carboxymethylcellulose   1%                                                   silicone oil (in the form of a 75%                                                                     1%                                                   aqueous emulsion)                                                             water                   32%                                                   ______________________________________                                    

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired dilution can be obtained by dilution with water. Such dilutionscan be used to treat living plants and plant propagation material byspraying, pouring or immersion and to protect them against infestationby microorganisms.

Biological Examples

A synergistic effect exists whenever the action of the active ingredientcombination is greater than the sum of the actions of the individualcomponents.

The action E to be expected for a given active ingredient combination,e.g. of two fungi-cides, obeys the COLBY formula and can be calculatedas follows (COLBY, S. R. "Calculating synergistic and antagonisticresponses of herbicide combination". Weeds, Vol. 15, pages 20-22; 1967):

ppm=milligram of active ingredient (=ai) per liter of spray mixture

X=% action by active ingredient I using p ppm of active ingredient

Y=% action by active ingredient II using q ppm of active ingredient and

E=the expected action of active ingredients I+II using p+q ppm of activeingredient

(additive action): ##EQU1##

If the action (O) actually observed is greater than the expected action(E), then the action of the combination is superadditive, i.e. there isa synergistic effect.

O/E=synergy factor (SF).

In the Examples that follow, the infestation of the untreated plants issaid to be 100%, which corresponds to an action of 0%.

Example 1: Action against Puccinia recondita on wheat

7-day-old wheat plants are sprayed to drip point with a spray mixtureprepared from a formulation of the active ingredient or activeingredient combination. After 48 hours the treated plants are infectedwith a conidia suspension of the fungus. The treated plants are thenincubated for 2 days at 90-100% relative humidity and 20° C. and placedin a climatic chamber at 21 ° C. for a further 9 days. 11 days afterinfection the fungal infestation is assessed. The following results areobtained:

                  TAB. 1                                                          ______________________________________                                        Compound mixture: IA = epoxiconazol, IIA = propiconazol                                                               Synergy                                                       % action        factor                                Test mg ai per liter    found   calculated                                                                            SF                                    No.  ai IA   ai IIA  I:II O       E       O/E                                 ______________________________________                                        0    --      --            0 (control)                                        1    0.6     --            0                                                  2    2       --           13                                                  3    --      0.2           0                                                  4    --      2             0                                                  5    --      6            35                                                  6    0.6     0.2     3:1  13      0       *                                   7    0.6     2       1:3  13      0       *                                   8    2       0.2     10:1 40      13      3.1                                 9    2       2       1:1  40      13      3.1                                 ______________________________________                                         *synergy factor cannot be calculated                                     

Example 2: Action against Erysiphe graminis on barley

6-day-old barley planks are sprayed to drip point with a spray mixtureprepared from a formulation of the active ingredient or activeingredient combination, After 2 days the plants are inoculated withspores of Erysiphe graminis and incubated in a greenhouse at 21° C. and60-70% humidity. After 11 days the fungal infestation is assessed. Thefollowing results are obtained:

                  TAB. 2                                                          ______________________________________                                        Compound mixture: IA = epoxiconazol, IIA = propiconazol                                                % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai IA   ai IIA  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.2     --             0                                                 2    0.6     --             0                                                 3    2       --            70                                                 4    --      0.06           0                                                 5    --      0.2            0                                                 6    --      0.6           50                                                 7    --      2             85                                                 8    0.2     0.2     1:1   50      0       *                                  9    0.2     0.6     1:3   65      50      1.3                                10   0.6     0.06    10:1  65      0       *                                  11   0.6     0.2     3:1   65      0       *                                  12   0.6     0.6     1:1   70      50      1.4                                13   2       0.2     10:1  85      70      1.2                                ______________________________________                                         *synergy factor cannot be calculated                                     

Examples 3-7/Tab. 3-7: Action against Erysiphe graminis on wheat7-day-old wheat plants are sprayed to drip point with a spray mixtureprepared from a formulation of the active ingredient or activeingredient combination. After 1 day the plants are inoculated withspores of Erysiphe graminis and incubated in a greenhouse at 20 ° C. and50-80% humidity. After 10 days the fungal infestation is assessed. Thefollowing results are obtained:

    ______________________________________                                        Example 3/Tab. 3: Compound mixture:                                           IB = fenbuconazol, IIA = propiconazol                                                                  % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai IB   ai IIA  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.06    --             0                                                 2    0.2     --            17                                                 3    0.6     --            42                                                 4    6                     48                                                 5    --      0.06          10                                                 6    --      0.6           13                                                 7    0.06    0.06    1:1   60      10      6                                  8    0.06    0.6      1:10 55      13      4.2                                9    0.2     0.06    3:1   49      25      2.0                                10   0.2     0.6     1:3   49      28      1.8                                11   6       0.6     10:1  75      55      1.4                                ______________________________________                                    

    ______________________________________                                        Example 4/Tab. 4: Compound mixture:                                           IC = metconazol, IIA = propiconazol                                                                    % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai IC   ai IIA  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.06    --             0                                                 2    0.2     --            10                                                 3    0.6     --            19                                                 4    2       --            22                                                 5    --      0.6            0                                                 6    --      2             64                                                 7    0.06    0.6      1:10 17      0       *                                  8    0.2     0.6     1:3   32      1       32                                 9    0.2     2        1:10 78      64      1.2                                10   0.6     0.6     1:1   38      19      2.0                                11   2       0.6     3:1   29      22      1.3                                ______________________________________                                         *synergy factor cannot be calculated                                     

    ______________________________________                                        Example 5/Tab. 5: Compound mixture:                                           ID = tetraconazol, IIA = propiconazol                                                                  % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai ID   ai IIA  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.06    --             1                                                 2    0.6     --            37                                                 3    6       --            47                                                 4    --      0.06          10                                                 5    --      0.6           13                                                 6    0.06    0.06    1:1   46      11      4.2                                7    0.06    0.6      1:10 35      14      2.5                                8    6       0.6     10:1  63      54      1.2                                ______________________________________                                    

    ______________________________________                                        Example 6/Tab. 6: Compound mixture:                                           IC = metconazol, IIB = cyprodinil                                                                      % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai IC   ai IIB  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.6     --            32                                                 2    2                     65                                                 3    6                     85                                                 4    --      2              8                                                 5    --      20            31                                                 6    0.6     2       1:3   59      37      1.6                                7    0.6     20       1:30 74      53      1.4                                8    2       2       1:1   80      68      1.2                                9    2       20       1:10 84      76      1.1                                10   6       2       3:1   92      86      1.1                                ______________________________________                                    

    ______________________________________                                        Example 7/Tab. 7: Compound mixture:                                           IF = bromuconazol, IIB = cyprodinil                                                                    % action                                             Test mg ai per liter     found   calculated                                                                            SF                                   No.  ai IF   ai IIB  I:II  O       E       O/E                                ______________________________________                                        0    --      --             0 (control)                                       1    0.1     --            35                                                 2    0.25                  44                                                 3    1       --            46                                                 4    5                     50                                                 5    --      0.5            0                                                 6    --      1              0                                                 7    0.1     0.5     1:5   62      35      1.8                                8    0.1     1        1:10 73      35      2.1                                9    0.25    0.5     1:2   54      44      1.2                                10   1       0.5     2:1   56      46      1.2                                ______________________________________                                    

What is claimed is:
 1. A plant microbicidal composition comprising atleast two active ingredient components in a synergistically effectiveamount, together with an inert carrier, wherein component I isepoxiconazol or a salt or metal complex thereof and component II ispropiconazol or a salt or metal complex thereof, wherein the weightratio of component I to component II is in the range of about 1:3 toabout 10:1.
 2. A composition of claim 1 wherein the ratio by weightI:II=1:3 to 3:1.
 3. A method of controlling and preventing theoccurrence of fungi on plants, which comprises treating a site infestedby or threatened with infestation by fungi with a fungicidally effectiveamount of component I and component II according to claim 1, in anydesired order or simultaneously.
 4. A method of claim 3 wherein cerealis treated.
 5. A method of claim 3 wherein seed is treated.